Due to the use of IV antibiotics to treat exacerbations, those with cystic fibrosis now have a life expectancy of about 50 years, which has increased from 10 years about 40 years ago.
Pseudomonas aeriginosa is the most prevalent bacterium which has been associated with decline in lung function amongst people with CF. this is usually responsive to antibiotic treatment, but the organism can develop a resistance to it. Multi-resistant P aeriginosa has been connected with severe lung disease, a decline in FEV1 and also end-stage lung disease.
CF patient who have multi-resistant P aeruginosa will require more frequent trips to hospital, and longer courses of antibiotics. This is not the only organism known to be resistant to a variety of antibiotics, there are also stenotrophomonas, maltophilia, achromobacter xyloxidans, and burkholderia cepacia complex, although these are less common than pseudomonas aeruginosa.
Generally CF patients in exacerbation will be given a combination of antibiotics, this will be determined by culture results of secretions. A combination is given to reduce the risk of the organism becoming resistant. Other factors to consider are how the patient has responded to treatment previously, allergies, antibiotic sensitivity and the type of organism as well as local policy.
Generally patients are given a two week course of antibiotics, although the course may be as short as 10 days, or as long as three weeks. Naturally a shorter course includes the risk of not completely clearing the infection, increasing the chance that the organism could become resistant to the antibiotics and allowing the infection to cause lung damage. There is no general consensus of length of IV course or in fact a uniform and comprehensive policy. Each trust has its own policy which is determined by current research, experience and knowledge as well as cost implications.